Throttling type fluid control valves are characterized by their ability to precisely control, or meter, flow through their flow openings, or ports, such openings being generally adjustable in size. Such valves may be for high pressure or low pressure use, suitable for use with caustic fluids, gases, etc. The present invention is directed to throttling control valves which exhibit precise flow control, are suitable for use in high pressure flowpaths and possess high operating efficiency, that is, do not substantially impede flow when in the open position.
The throttling valve of the present invention is of the movable disc type and has a pair of machined, relatively adjustable throttling discs with corresponding ports. Movement of the discs relative to each other varies the size of the ports in the flowpath and thus controls fluid flow.
There are a number of different types of disc valves in the prior art, although many are unsuitable for use in high pressure flow lines. Those that are used in high pressure flow lines generally have a disc operating mechanism situated in the downstream side of the flow line to control the size of the port openings and hence, the fluid flow. Therefore, such mechanisms are generally of heavy construction to withstand the high pressure flow. One prior art valve has a stationary disc and a movable disc that is operated by a rotational fork that engages the disc periphery. In one version, the flowpath turns just downstream of the fork so that the operating mechanism for the fork is not in the flowpath. In another version, an operating handle protrudes from the side of the valve body to permit the operating mechanism to be out of the flowpath. The mechanism in both versions is massive, quite complicated to manufacture and assemble and appears to be quite expensive.
Prior art disc type throttling valves for high pressure applications are also unidirectional, usually having one fixed disc and one movable disc which is generally movably mounted to the fixed disc at its axis. They often use the flowpath pressure to help provide a seal. They are not suitable for use in bidirectional flowpaths and, unless of expensive construction, are not generally useful in high pressure flowpaths.